Samsung Galaxy S4 I9505 users who have already updated their devices with Android 4.4.2 XXUFNA5 KitKat, may root their devices using the tutorial below.

This tutorial uses CF-Auto-Root file released by Senior Recognized XDA-Developers, Chainfire. Head over to the CF-Auto-Root main thread to learn more about the root method.
Disclaimer: Rooting voids the warranty of your device. We and the developer of this rooting procedures shall not be held responsible if any undesirable outcomes may happen to your device. use of this root guide is solely at your own risk!

Pre-requisites
1. Install USB Drivers for Samsung Galaxy S4 on the computer.
2. Enable USB Debugging Mode on the phone by navigating to Settings >> Developer Options.
3. Make a backup of all your important data before following the guide.
4. The Galaxy S4 should be factory unlocked and not locked to any particular carrier.
5. Ensure the battery of the phone is charged more than 80 percent.
6. The CF-Auto-Root file works only on the LTE version of the Samsung Galaxy S4 (GT-I9505). Applying this to any incorrect variant might brick the device. Verify the model number of the Galaxy S4 by navigating to Settings >> About Phone.

Steps to Root Galaxy S4 I9505 Running on Android 4.4.2 XXUFNA5 KitKat FirmwareStep 1: Extract CF-Auto-Root and Odin 3.07 files using WinRAR/7-Zip/WinZip or any other extracting tool.Step 2: Switch off the Galaxy S4. Then boot the device into Download Mode by pressing and holding Volume Down, Home and Power buttons together until a construction Android robot icon with a warning triangle appears on screen. Now press the Volume Up button to enter Download Mode.Step 3: Launch Odin on the computer as an Administrator.Step 4: Connect the Galaxy S4 to the computer using USB cable while it is in the Download Mode. Wait until Odin detects the device. When the device is connected successfully, the ID: COM box will turn to light blue with the COM port number. Additionally, the successful connected will be indicated by a message saying Added.

Note: If the Added message does not appear, then try re-install USB drivers or changing the port on the computer.Step 5: In Odin, click the PDA button and select the CF-Auto-Root-jflte-jfltexx-gti9505.tar.md5 file.Step 6: Verify that Auto Reboot and F. Reset Time checkboxes are selected in Odin. Also, ensure the Re-Partition option is NOT selected.Step 7: Double-check and click Start in Odin. The installation process will now begin.Step 8: Once the installation process completes, your phone will restart and soon you will see a PASS message with green background in the left-most box at the very top of the Odin. You can now unplug the USB cable to disconnect your device from computer.

Samsung Galaxy S4 I9505 running on Android 4.4.2 XXUFNA5 KitKat is now rooted successfully. You can now install any app that requires root permission. Verify the root status of the device by downloading Root Checker app from Google Play Store.

Thank's to all fellas at XDA who first tried out this rooting technique. This method was originally posted via XDA-Developers original thread.